Antibackup mechanism for the takeup spool in a film cartridge

ABSTRACT

An antibackup mechanism in a movie film cartridge is disclosed, which prevents reverse rotation of the takeup spool. In the preferred embodiment the mechanism is a ratchet coupling between the spool and the cartridge housing, comprising a first ratchet member mounted in the cartridge for movement transverse to the axis of rotation of the spool, and a second ratchet member mounted on the spool for rotation therewith and for axial movement between a first position in which the ratchet members cooperate to prevent rotation of the spool in one direction and permit rotation of the spool in the opposite direction for winding up film, and a second position in which the ratchet members are disabled. The second ratchet member has a detent biased radially toward engagement with a notch defined by the spool. The notch has a ramp surface inclined with respect to the axis of rotation of the spool so that the detent and notch cooperate to releasably retain the second ratchet member when it is in the first position and to urge the second ratchet member toward that first position when it is in the second position. In addition the ratchet member on the spool can include a cup-shaped portion defining a cylindrical bore that slidably fits over a cylindrical projection on the spool to assure correct alignment of the ratchet member with respect to the spool when the ratchet member is being moved axially.

United States Patent [72] lnventors Evan A. Edwards; Primary Examinr- Leonard D. Christian Robert C. Sutliff, both 01 Rochester, N.Y. Attorneys- Robert W Hampton and William F. Delaney, Jr. [211 App]. No. 838,276 [22] Filed July 1,1969 i 5 patented J 15, 1971 ABSTRACT: An antibackup mechanism 111 a mov e film car- 73 Assignee Eastman Kodak Company tridge is disclosed, which prevents reverse rotation of the Rochester, N.Y. takeup spool. In the preferred embodiment the mechanism 18 a ratchet coupling between the spool and the cartridge housing, comprising a first ratchet member mounted in the cartridge for movement transverse to the axis of rotation of the spool, ANTIBACKUP MECHANISM FOR THE TAKEUP and a second ratchet member mounted on the spool for rota- SPOOL IN A FILM CARTRIDGE tion therewith and for axial movement betweena first position 4 Chill", 4 Drlwill! 8 in which the ratchet members cooperate to prevent rotation of 52] us. Cl 242/198, dhechm' and Permit mmhh in 3 5 2 /72 the opposite direction for winding up film, and a second posi- 511 Int. Cl. G03b 1/04, which ratchet members are disabled- The secmd G1 lb 1552,61 1b 23/04 ratchet member has a detent biased radially toward engage- 501 Field olsearch 242/712, with a defined by The has a 193,194, l97 200;352/72 78,156 surface inclined with respect to the axis of rotation of the spool so that the detent and notchcooperate to releasably 55] R mm Cit d retain the second ratchet member when it is in the first posi- UNITED STATES PATENTS tion and tohurge the second ratchzt merirber aowaglthat fiast position w en it is in t e secon posi ion. n a mom t e ratchet member on the spool can include a cup-shaped por- 3 3 12,1968 winner et al 352/78 tion defining a cylindrical bore that sliclably fits over a cylin- I drical projection on the spool to assure correct alignment of FOREIGN PATENTS the ratchet member with respect to the spool when the ratchet 6,916,866 4/1969 Germany 242/198 member is being moved axially.

' 1 Fl F 30 E I 2! I9 34 20 I s" he 6 a I PATENTEDJUNISIBH 3584.806

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37 I REVERSIBLE DRIVE 32 CAMERA MOTOR EVAN A. EDWARDS ROBERT .C. TLIFF INV TORS 3 BY MM Rm w ATTQRNEYS ANTIBACKUP MECHANISM FOR THE TAKEUP SPOOL IN A FILM CARTRIDGE CROSS-REFERENCE TO RELATED APPLICATION Reference is made to commonly assigned, copending US Pat. application Ser. No. 838,275, entitled AN AN- TIBACKUP MECHANISM IN A FILM CARTRIDGE AND MEANS IN A CAMERA FOR DISABLING THE MECHANISM, filed July 1, 1969, in the names of Edwards et al.

BACKGROUND OF THE INVENTION The present invention relates to film cartridges in which a roll of film is sealed before, during and after exposure in a camera, and more particularly to such cartridges having a disengageable antibackup device for the takeup spool.

Many commercially available movie camera cartridges include a substantially rectangular housing in which a supply roll of film and a takeup spool are rotatably mounted in a side-byside coaxial relation, such as disclosed for example in U.S. Pat. No. 3,208,686 issued Sept. 28, 1965 in the name of E. A. Edwards et al. As initially loaded, a film leader is pulled from the supply roll, threaded past an exposure aperture in an end wall of the cartridge and then attached to the takeup spool. After being so loaded with unexposed film, the housing is closed and sealed by one or more covers.

When the film in such a cartridge is to be exposed, the cartridge is placed in a motion picture camera adapted to accommodate the cartridge, and a film advancing mechanism in the camera engages perforations in the film during operation of the camera to intermittently pull film from the supply coil and transport it past the exposure aperture to the takeup spool. A takeup drive in the camera is coupled to the takeup spool of the cartridge to positively drive the spool to wind up the exposed film. I

Usually suchcartridges include devices to overcome the tendency of coiled film to clockspring when the cartridge is subjected to sharp movements. The term clockspring," as used herein, means radial displacement of successive outer convolutions of a film roll, caused by the tendency of the roll to unwind. Anticlockspring devices in the takeup chamber of most commercial cartridges operate on the takeup spool in such a manner that reverse rotation of the spool is prevented, so that film on the spool cannot be unwound. Such devices often comprise a ratchet arrangement wherein a shuttle with a plurality of teeth engages teeth on the spool to prevent rotation of the spool in one direction. However, such devices prevent the film from being driven in a reverse direction for photographing double-exposure fade, lap and dissolve sequence or for removal of the exposed film through the exposure aperture of the cartridge.

To produce fade, lap and dissolve" sequences with presently available commercial cartridges, some cameras have been provided with a feature permitting the operator to advance a predetermined number of frames of film past the exposure aperture, during which the exposure aperture is gradually reduced and the takeup drive n the camera is stopped. The film thus exposed is collected loosely in the takeup chamber, and the camera can then be driven in reverse to enable the operator to make a second sequence of exposures on the previously exposed film with the exposure aperture gradually increased to obtain a fade, lap and dissolve" sequence. The difficulty with such an arrangement is that it requires space within the takeup chamber to receive film without winding it up. Yet, when almost all ofa roll of film has been exposed, there is very little space remaining in the takeup chamber to receive the unwound film, so that an attempt to produce a "fade, lap and dissolve" sequence near the end of the roll will frequently cause the film to jam in the cartridge. Accordingly, it is preferred to wind exposed film onto the takeup spool and then to disable the antibackup mechanism and drive the film in reverse for taking an overlapping fade, lap and dissolve sequence.

Such an antibackup mechanism would also permit easier unloading of exposed film from the cartridge, since the exposed film could be unwound from the takeup spool and removed through the exposure aperture without breaking the cartridge open.

It is known in the prior art to provide film cartridges with antibackup devices, which prevent reverse rotation of the takeup spool, and which can be disabled without opening the cartridge. The antibackup device in one such cartridge comprises a slide member mounted on the spool for engaging the antibackup shuttle in one position to prevent reverse rotation of the spool, and the slide can be depressed to a second position in which the mechanism is disabled. However, in such a cartridge the slide member is biased toward the shuttle-engaging position by a coil spring mounted between the spool and the slide member, and the manufacturing tolerance of the resilient force provided by such a spring must be carefully predetermined and maintained to assure proper operation of the slide member, particularly when it is being depressed from the exterior of the cartridge against the spring bias.

SUMMARY OF THE INVENTION It is an object of this invention to provide a film cartridge having an improved antibackup device of the type described above that can be disabled without opening the cartridge to permit photographing fade, lap and dissolve" sequences and to simplify film removal from the cartridge.

According to this invention a film cartridge having a takeup spool rotatably mounted in a takeup chamber is provided with an antibackup mechanism comprising a first member mounted in the cartridge for movement transverse to the axis of rotation of the spool, and a second member mounted on the spool for rotation therewith and for movement between a first position in which the members cooperate to prevent rotation of the spool in one direction and permit rotation in the opposite direction for winding up film and a second position in which the members are disabled. The second member has a portion which can be engaged from the exterior of the cartridge, and a detent portion biased radially toward engagement with a notch defined by the spool to releasably retain the second member in one of its positions. The notch in the spool has an inclined surface that is engageable by the detent to urge the second member toward that retained position when the second member is in its other position.

According to the preferred embodiment of this invention, the second member is slidably mounted on the spool for axial movement, and this slide member comprises a plurality of resiliently flexible fingers extending parallel to the axis of rotation of the spool to define detents biased by the resiliency of the fingers toward engagement with the notches in the spool. Thus, the required resilient force is provided by the member itself, and the need for an independent spring is eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a cartridge according to the invention showing the takeup side of the cartridge, and portions of the takeup spool and antibackup mechanism according to the present invention;

FIG. 2 is a cross-sectional view of the cartridge shown in FIG. 1 taken along the lines 2-2;

FIG. 3 is a cross-sectional view of the cartridge shown in FIG. 1 taken along the lines 3-3 showing a plane view of one member of the antibackup mechanism according to the invention; and

FIG. 4 is a cross-sectional view of a portion of the cartridge, similar to FIG. 2, but with the antibackup device disabled by a projection on a camera.

DETAILED DESCRIPTION OF THE DRAWINGS As shown in the drawings, a film cartridge 10 according to a preferred embodiment of this invention is shown having an antibackup mechanism for the takeup spool, which can be disengaged from the exterior of the cartridge. In FIG. 1 the cartridge is shown having a rectangular housing 12, an exposure aperture 13, and an aperture 14 through which the takeup spool 11 is engageable from the exterior of the cartridge housing 12.

Q As seen in FIG. 2 the cartridge 10 includes an internal partition 15 which divides the housing 12 into a supply chamber 16 and a takeup chamber 17. Located in the supply chamber 16 is a hub 18 mounted on the partition 15 for locating a supply roll of film. Mounted on the inside of the hub 18 is a post 19 extending through an aperture 20 in the partition 15 and into the takeup chamber 17. The takeup spool 11 is mounted for rotation on the post 19 for receiving and winding up exposed film F. As initially loaded, a film leader is pulled from the supply roll, threaded past the exposure aperture 13 and guided through a film path to the takeup chamber 17 where the lead end of the film is attached to the takeup spool 1 1.

To prevent film wound on the takeup spool from clockspringing, the cartridge 10 includes an antibackup mechanism, which in this preferred embodiment is a ratchet comprising a shuttle member 21 mounted in the cartridge for movement transverse to the axis of rotation of the spool, and a slide member 22 mounted on the spool for rotation therewith and for axial movement with respect to the shuttle 21. The slide member 22 has one or more fingers 23 extending parallel to the axis of rotation of the spool. Each finger 23 has a detent 24 that is engageable within a notch 25 defined by the spool 11. The notch 25 has a ramp surface 26 inclined with respect to the axis of rotation of the spool.

As seen more clearly in FIG. 3 the shuttle 21 has inwardly extending teeth 27 which are engageable with the fingers 23 of the slide member 22. The teeth 27 define gradually inclined surfaces 28 and sharply inclined surfaces 29, such that rotation of the takeup spool in a clockwise direction as viewed from the takeup side of the cartridge will cause the shuttle 21 to oscillate transversely to the axis of rotation of the spool with little resistance provided by the gradually inclined surfaces 28 of the teeth 27. However, rotation of the spool in a counterclockwise direction will cause a finger 23 on the slide 22 to engage the sharply inclined surface 29 of one of the teeth 27 on the shuttle so that rotation of the slide member and the spool is prevented in that direction and film cannot be unwound from the spool.

As seen in FIG. 4 the antibackup mechanism of the cartridge 10 can be disabled by depressing the slide member 22 to a position in which-a recess 30 in the finger 23 is aligned with the shuttle 21 to enable the spool to be rotated in a counterclockwise direction without interference with the shuttle. When the slide member 22 is depressed, the detent 24 on the finger 23 rides outwardly on the ramp 26 of the notch 25 and flexes the finger 23 radially outwardly. The resiliency of the finger 23 biases the detent radially inwardly against the ramp, and thereby biases the detent 24 into the notch 25 to urge the slide member into a raised position in which the antibackup mechanism is operative. When the slide member is in its raised position the resiliency of the finger 23 releasably retains the detent 24 in the notch 25 to hold the slide member in that position.

The slide member 22 includes a cup-shaped portion 40, engageable from the exterior of the cartridge and defining an interior bore 41 that slidably fits on a cylindrical projection 42 on the spool 11. This cup-shaped portion permits the slide member to be depressed by a member engaging it on the axis of rotation which reduces the friction required to turn the spool when the slide member is depressed. The sliding engagement of the projection 42 of the spool in the bore 41 of the cup-shaped portion also insures a proper alignment of the slide member with respect to the spool, which is particularly important when the cartridge is being inserted in the camera or when the slide member is being depressed.

The slide member in the cartridge can be depressed by any suitable apparatus. A preferred mechanism in a motion pic ture camera mechanism for depressing the slide member is shown at FIG. 4 for disabling the antibackup mechanism of the cartridge when it is operatively positioned in the camera to enable an operator to photograph overlapping fade, lap and dissolve" sequences. Such a camera, a portion of which is indicated at 31, would include a reversible drive motor 32, and an exposure control system (not shown) for gradually varying exposure conditions during a "fade, lap and dissolve" sequence. Such a reversible motor and exposure control system are well known in the art and need not be described in detail herein.

The motor 32 drives a reversible pulldown claw (not shown) and a shaft 33 to which a driving plate 34 is attached. When the cartridge is loaded in the camera, the spool 11 is positioned with its axis of rotation substantially aligned with the axis of rotation of the shaft 33 and plate 34. A drive lug 35 on the plate 34 extends toward the spool and is offset from the axis of rotation of the plate to drivingly engage either side of a drive lug 36 on the spool to drive the spool in either direction. The slide member 22 is shown depressed by a pin 37 which extends through an axial bore 38 in the shaft 33. The pin 37 could be mounted on the shaft 33 or on plate 34, but in most commercially available movie cameras the drive plate is biased axially toward the spool to assure engagement of the drive lugs 35 and 36. The cup-shaped portion 40 of the slide member 22 enables the slide to be depressed by a camera projection mounted independently of the bias on the drive plate 34 and permits the slide to be depressed to any desired depth without requiring the drive lug 35 be extended. A further advantage of the camera mechanism shown in FIG. 4 is that the slide member 22 is depressed by engagement of pin 37 along the axis of rotation of the slide and spool. This arrangement reduces friction and avoids the application of additional stress on the plate 34 and lug 35, and consequently wear and strain on these and other drive parts is reduced. In a camera which is not provided with a reverse drive, the drive plate 34 would not be provided with a detent 37, and the slide member 22 would remain in a raised position in which the antibackup mechanism would be operative to prevent reverse rotation of the spool.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. In a motion picture film cartridge having a housing defining an exposure aperture, means defining atakeup chamber within the housing, and means for guiding film past the exposure aperture to the takeup chamber, the combination comprising:

a takeup spool rotatably mounted in the takeup chamber, said spool defining a notch having a surface inclined with respect to the axis of rotation of the spool;

a first member mounted in the cartridge for movement transverse to the axis of rotation of the spool; and

a second member mounted on the spool for rotation therewith and for axial movement between a first position in which said members cooperate to prevent rotation of the spool in one direction and to permit rotation of the spool in the opposite direction for winding up film, and a second position in which said members are disabled, said second member having a detent portion biased radially toward engagement with said notch to rcleasably retain said second member in one of such positions, said detent being engageable with said inclined surface of said notch to urge said second member toward that position when said second member is in the other of said positions.

2. ln'a motion picture film cartridge having a housing defining an exposure aperture, meansdefining a takeup chamber within the housing, and means for guiding film past the exposure aperture to the takeup chamber, the combination comprising:

a takeup spool rotatably mounted in the takeup chamber,

said spool defining a plurality of notches having a surface inclined with respect to the axis of rotation of the spool;

first member mounted in the cartridge for movement transverse to the axis of rotation of the spool; and

second member mounted on the spool for rotation therewith and for axial movement thereon, said second member having a plurality of resiliently flexible finger portions extending parallel to the axis of rotation of the spool, each of said finger portions having a detent biased by the resiliency of the fingers toward engagement with one of the notches in the spool, said second member being movable between a first position in which the detents are engaged within the notches in the spool and in which the fingers cooperate with the first member to prevent rotation of the spool in one direction and permit rotation of the spool in the opposite direction for winding up film, and

a second position in which the detents engage the inclined surfaces of the notches to flex the fingers radially outwardly against the resilient bias of the fingers and in which said fingers are disengaged from the first member to disable the backup mechanism, said second member being biased toward the first position from the second position by the bias of detents against the inclined surfaces of the notches in the spool.

The invention as claimed in claim 2 wherein the detents have ramp surfaces inclined at an angle with respect to the axis of rotation of the spool, said ramp surfaces being engageable with the inclined surfaces of the notches to resist axial movement of the second member from the first position to the second position, and to urge the second member toward the first position when it is in the second position.

4. in a motion picture film cartridge having a housing defining an exposure aperture, means defining a takeup chamber within the housing, and means for guiding film past the exposure aperture to the takeup chamber, an antibackup ratchet mechanism comprising:

a takeup spool rotatably mounted in the takeup chamber, said spool defining a notch having a surface inclined with respect to the axis of rotation of the spool;

a shuttle member mounted in the cartridge for movement transverse to the axis of rotation of the spool; and

a slide member mounted on the spool for rotation therewith and for axial movement between a first position in which said members cooperate to prevent rotation of the spool in one direction and to permit rotation of the spool in the opposite direction for winding up film, and a second position in which said members are disabled, said slide member having a detent portion biased radially toward engagement with said notch to releasably retain said slide member in one of such positions, said detent being engageable with said inclined surface of said notch to urge said slide member toward that position when said slide member is in the other of said positions. 

1. In a motion picture film cartridge having a housing defining an exposure aperture, means defining a takeup chamber within the housing, and means for guiding film past the exposure aperture to the takeup chamber, the combination comprising: a takeup spool rotatably mounted in the takeup chamber, said spool defining a notch having a surface inclined with respect to the axis of rotation of the spool; a first member mounted in the cartridge for movement transverse to the axis of rotation of the spool; and a second member mounted on the spool for rotation therewith and for axial movement between a first position in which said members cooperate to prevent rotation of the spool in one direction and to permit rotation of the spool in the opposite direction for winding up film, and a second position in which said members are disabled, said second member having a detent portion biased radially toward engagement with said notch to releasably retain said second member in one of such positions, said detent being engageable with said inclined surface of said notch to urge said second member toward that position when said second member is in the other of said positions.
 2. In a motion picture film cartridge having a housing defining an exposure aperture, means defining a takeup chamber within the housing, and means for guiding film past the exposure aperture to the takeup chamber, the combination comprising: a takeup spool rotatably mounted in the takeup chamber, said spool defining a plurality of notches having a surface inclined with respect to the axis of rotation of the spool; a first member mounted in the cartridge for movement transverse to the axis of rotation of the spool; and a second member mounted on the spool for rotation therewith and for axial movement thereon, said second member having a plurality of resiliently flexible finger portions extending parallel to the axis of rotation of the spool, each of said finger portions having a detent biased by the resiliency of the fingers toward engagement with one of the notches in the spool, said second member being movable between a. a first position in which the detents are engaged within the notches in the spool and in which the fingers cooperate with the first member to prevent rotation of the spool in one direction and permit rotation of the spool in the opposite direction for winding up film, and b. a second position in which the detents engage the inclined surfaces of the notches to flex the fingers radially outwardly against the resilient bias of the fingers and in which said fingers are disengaged from the first member to disable the backup mechanism, said second member being biased toward the first position from the second position by the bias of detents against the inclined surfaces of the notches in the spool.
 3. The invention as claimed in claim 2 wherein the detents have ramp surfaces inclined at an angle with respect to the axis of rotation of the spool, said ramp surfaces being engageable with the inclined surfaces of the notches to resist axial movement of the second member from the first position to the second position, and to urge the second member toward the first position when it is in the second position.
 4. In a motion picture film cartridge having a housing defining an exposure aperture, means defining a takeup chamber within the housing, and means for guiding film past the exposure aperture to the takeup chamber, an antibackup ratchet mechanism comprising: a takeup spool rotatably mounted in the takeup chamber, said spool defining a notch having a surface inclined with respect to the axis of rotation of the spool; a shuttle member mounted in the cartridge for movement transverse to the axis of rotation of the spool; and a slide member mounted on the spool for rotation therewith and for axial movement between a first position in which said members cooperate to prevent rotation of the spool in one direction and to permit rotation of the spool in the opposite direction for winding up film, and a second position in which said members are disabled, said slide member having a detent portion biased radially toward engagement with said notch to releasably retain said slide member in one of such positions, said detent being engageable with said inclined surface of said notch to urge said slide member toward that position when said slide member is in the other of said positions. 